QUERY DB ORACLE

In Oracle puoi usare listagg() , ma non ha distinct opzione. Quindi, usa una sottoquery e due livelli di aggregazione:

select listagg(id, ',') within group (order by id) as id, name, sum(cnt)
from (select id, name, count(*) as cnt
      from t
      group by id, name
     ) x
group by name;